The present invention relates to a recyclable support material comprising a cellulose containing carrier and at least one polymeric water resistant layer, as well as a process for the recycling of the support material.
It is known that support materials with polymeric water resistant layers on cellulose containing carriers are difficult to recycle.
One support material which is frequently used is a laminate of thermoplastic polymers, mostly polyethylene and paper. Known products of this type are, for example, beverage packaging materials and photographic support materials. The process of recycling them breaks these support materials down into the individual components in order to obtain the components in the purest possible form and to make them accessible in a separate process to reuse. This is described, for example, in the published German patent applications DE 4 105 368 and DE 4 042 225.
The development and optimization of such recycling processes have still not on the whole been fully achieved. Moreover, prior processes entail considerable expense in the practice of the process technology.
Radiation cured layers on cellulose containing carriers have become more widespread in various technical areas in recent years. These areas include photographic support materials, thermal recording materials, packaging materials, decorative and overlay papers, and separating and interleaving papers. These cellulose containing carriers with radiation cured layers can also have additional functional layers, such as, for example, barrier layers, image receiving layers, prints, metallic vapor deposits and the like.
In these product applications the suitability of use benefits from the chemical resistance (and non-destructibility) of the cured layers. For example, neither image carriers nor kitchen papers (decorative papers) are intended to rapidly wear out. Nevertheless the scrap which occurs in production, such as for example upon start up of a coating machine, accumulates in the individual production stages of these products. Therefore, it would be highly desirable from both economic and environmental viewpoints if this scrap or waste could to the greatest extent possible be completely conveyed back into the materials cycle.
However, the radiation cured layers, cannot be removed from the cellulose containing carriers, as is possible in the case of thermoplastic polyethylene. They are also not dissolvable in aqueous or organic solvents, and during a mechanical crushing of the layer material, either fragments accumulate which are too large or the crushing process must be carried out in such an intensive manner that the fibers of the cellulose containing carrier lose their functionality.
It is, therefore, an object of the present invention to make available a recyclable layer material comprising a cellulose containing carrier, and at least one polymeric water resistant layer which without additional expense can be conveyed back into the production stream by means of equipment and processes which are conventional in the paper industry.